skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Radiative Decays of Low-Lying Excited-State Hyperons

Abstract

The quark wave-functions of the lower-lying excited-state hyperons Lambda(1405), Sigma(1385), and Lambda(1520) are not well understood. For example, the Lambda(1405) may not be a regular three-quark state but a $$\bar{K}$$N molecule. Several competing models have been proposed, but none have been convincingly eliminated. Measuring radiative decays provides a means of discriminating between the models. The radiative branching of ratios are predicted to be small (~1%), but the radiative widths vary by factors of 2-10 from model to model. The existing experimental data is sparse and inconsistent; moreover, the radiative decay of the Sigma(1385) has never been observed before (except for one event). These lower-lying excited state hypersons were produced in a tagged photon-beam experiment in the CLAS detector at TJNAF in the reaction gamma p → K + Y* for photon energies from threshold to 2.4 GeV. The radiative branching ration for the Sigma 0(1385) relative to the Sigma 0(1385) → Lambda pi 0 channel was measured to be 0.021 ± 0.008$$+0.004\atop{-0.007}$$, corresponding to a partial width of 640 ± 270$$+130\atop{-220}$$ keV.

Authors:
 [1]
  1. Rice Univ., Houston, TX (United States)
Publication Date:
Research Org.:
Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
824879
Report Number(s):
JLAB-PHY-00-67; DOE/ER/40150-2737
TRN: US0402190
DOE Contract Number:  
AC05-84ER40150
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: TH: Thesis (Ph.D.)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; EXCITED STATES; HYPERONS; PHOTONS; QUARKS; RADIATIVE DECAY; WAVE FUNCTIONS

Citation Formats

Taylor, Simon. Radiative Decays of Low-Lying Excited-State Hyperons. United States: N. p., 2000. Web. doi:10.2172/824879.
Taylor, Simon. Radiative Decays of Low-Lying Excited-State Hyperons. United States. doi:10.2172/824879.
Taylor, Simon. Mon . "Radiative Decays of Low-Lying Excited-State Hyperons". United States. doi:10.2172/824879. https://www.osti.gov/servlets/purl/824879.
@article{osti_824879,
title = {Radiative Decays of Low-Lying Excited-State Hyperons},
author = {Taylor, Simon},
abstractNote = {The quark wave-functions of the lower-lying excited-state hyperons Lambda(1405), Sigma(1385), and Lambda(1520) are not well understood. For example, the Lambda(1405) may not be a regular three-quark state but a $\bar{K}$N molecule. Several competing models have been proposed, but none have been convincingly eliminated. Measuring radiative decays provides a means of discriminating between the models. The radiative branching of ratios are predicted to be small (~1%), but the radiative widths vary by factors of 2-10 from model to model. The existing experimental data is sparse and inconsistent; moreover, the radiative decay of the Sigma(1385) has never been observed before (except for one event). These lower-lying excited state hypersons were produced in a tagged photon-beam experiment in the CLAS detector at TJNAF in the reaction gamma p → K+ Y* for photon energies from threshold to 2.4 GeV. The radiative branching ration for the Sigma0(1385) relative to the Sigma0(1385) → Lambda pi0 channel was measured to be 0.021 ± 0.008$+0.004\atop{-0.007}$, corresponding to a partial width of 640 ± 270$+130\atop{-220}$ keV.},
doi = {10.2172/824879},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2000},
month = {5}
}

Thesis/Dissertation:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this thesis or dissertation.

Save / Share: